topic Re: mapview.hitTest doesn't return results if opacity is set in ArcGIS JavaScript Maps SDK Questions

mapview.hitTest doesn't return results if opacity is set

JackFairfield — Tue, 03 Oct 2017 00:04:30 GMT

Why doesn't the mapview.hitTest method return any results?

Consider the simple example below:

If you modify this sample:

Access features with pointer events | ArcGIS API for JavaScript 4.5

and add the opacity property to the feature layer like this

...
var layer = new FeatureLayer({
url: "https://sampleserver6.arcgisonline.com/arcgis/rest/services/Hurricanes/MapServer/1",
opacity: .4,
outFields: ["*"]
});
...

The hit test response will not contain and values in the results array.

Here is a jsbin link showing what I am talking about:

JS Bin - Collaborative JavaScript Debugging

Re: mapview.hitTest doesn't return results if opacity is set

RobertScheitlin__GISP — Tue, 03 Oct 2017 12:44:33 GMT

Jack,

that is definitely a bug because when you revert back to 4.4 it works.

Re: mapview.hitTest doesn't return results if opacity is set

ThomasSolow — Tue, 03 Oct 2017 13:58:20 GMT

Yeah, looks like a bug to me. Seems that anything less than 1.0 opacity doesn't work with hitTest in a MapView.

Re: mapview.hitTest doesn't return results if opacity is set

JackFairfield — Tue, 03 Oct 2017 15:22:09 GMT

What can I expect for a bug fix like this? Do I have to wait for 4.6 for a fix?

Re: mapview.hitTest doesn't return results if opacity is set

ThomasSolow — Sat, 11 Dec 2021 22:30:11 GMT

I'm not sure.

You could use something like this for the time being:

// evt: ClickEvent, view: MapView
function getFeatures(evt, view){
  const pxRatio = view.extent.width / view.width,
        // number of pixels to check in
        pixelBuffer = 6,
        halfExtent = pxRatio * pixelBuffer,
        clickExtent = new Extent({
          xmin: evt.mapPoint.x - halfExtent,
          xmax: evt.mapPoint.x + halfExtent,
          ymin: evt.mapPoint.y - halfExtent,
          ymax: evt.mapPoint.y + halfExtent,
          spatialReference: view.extent.spatialReference
        });
              
  let queries = view.layerViews.map(lv => {
    let q = lv.layer.createQuery();
            
    q.geometry = clickExtent;
    q.geometryType = "esriGeometryEnvelope";
    q.outFields = null;
    q.where = null;
    return lv.queryFeatures(q);
  }).toArray();
          
  return Promise.all(queries).then(results => {
    return [].concat.apply([], results);
  });
}‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

example: JS Bin - Collaborative JavaScript Debugging

This won't work as well as hitTest. If you rely on this, it may be better to stick with 4.4 for the time being.

Re: mapview.hitTest doesn't return results if opacity is set

JackFairfield — Tue, 03 Oct 2017 17:01:31 GMT

Thanks for the work around. This doesn't seem to be fully working either unfortunately though. Try clicking the biggest bubble in the example on the bottom right side. It doesn't log any results. Is there a place where I can track a bug like this and watch for fixes?

Re: mapview.hitTest doesn't return results if opacity is set

ThomasSolow — Tue, 03 Oct 2017 18:06:58 GMT

Another workaround that seems to work is setting the layer's opacity to 1.0 but using a renderer to specify a symbol with opacity less than 1.0. This doesn't seem to interfere with hitTest: https://codepen.io/solowt/pen/PJJLrw?editors=1000#0

I reported the issue and I'll post here if I learn when it's going to be fixed.

Re: mapview.hitTest doesn't return results if opacity is set

JackFairfield — Tue, 03 Oct 2017 18:45:42 GMT

This does work as a temporary work around. Thanks Thomas.

Re: mapview.hitTest doesn't return results if opacity is set

ThomasSolow — Wed, 18 Oct 2017 16:07:14 GMT

Looks like this will be fixed in 4.6, sometime in early December.

Re: mapview.hitTest doesn't return results if opacity is set

JackFairfield — Thu, 19 Oct 2017 20:17:15 GMT

Thanks for following up on this Thomas.

Re: mapview.hitTest doesn't return results if opacity is set

DavidColey — Fri, 20 Oct 2017 17:44:01 GMT

Thanks for the info on this Thomas et al, I thought I was going crazy. I'm hoping the highlight for 2D will be available soon as well, since hitTest only works on the top-most feature

Re: mapview.hitTest doesn't return results if opacity is set

JackFairfield — Thu, 14 Dec 2017 19:05:39 GMT

Just to confirm. This is resolved when using the 4.6 version of the api.

Re: mapview.hitTest doesn't return results if opacity is set

DavidColey — Thu, 14 Dec 2017 20:28:11 GMT

Regardless that the API Reference

Popup | API Reference | ArcGIS API for JavaScript 4.6

still says only works in 3d?

Re: mapview.hitTest doesn't return results if opacity is set

JackFairfield — Mon, 18 Dec 2017 15:47:02 GMT

You are referencing something unrelated. There is a hitTest method in both MapViews and SceneViews. The sample should work in 2d and 3d.

MapView | API Reference | ArcGIS API for JavaScript 4.6

Re: mapview.hitTest doesn't return results if opacity is set

DavidColey — Mon, 18 Dec 2017 18:43:06 GMT

Sorry about that, yes of course. For some reason I was thinking hightlightSymbol